The Chamak-class missile boats (NATO code: Osa II class) of the Indian Navy were an Indian variant of the Soviet Project 205 Moskit.

The Osa-II Class missile boats formed the 25th Missile Vessel (K25) Squadron, also known as the Killers, based at Vizag. Osa is the Russian word for Wasp. All eight missile boats have been decommissioned from service.

Ships of the class

NamePennantCommissionedDecommissionedFateNotes
PrachandK9017 February 197629 December 1999
PralayaK9117 February 19768 June 2001
PratapK9217 February 197617 May 1996
PrabalK9317 February 197629 December 1999Preserved at EsselWorld, Gorai, MaharashtraFree Entry to visitors of the amusement park
ChapalK944 November 19765 May 2005Preserved at Karwar, Karnataka
ChamakK954 November 19765 May 2005Preserved at NDA, Khadkavasla
ChatakK969 February 19775 May 2005Preserved at SNC HQ, Kochi. The propeller has been gifted to Department of Ship Technology, CUSAT.
CharagK9717 October 197717 May 1996